"Created By" search Criteria Working for WTDocs only

Hi,

We Have one Customized serach...

Normaly We make a Customized Softtypes of WTDocument .

As exm.

- In Type And Attribute Manager

* Document

      * Customized Type

               * Customized Doc

               * Customized EPMDoc

When we Select"Search Type = Customized Type"  with Created By Criteria in Critea field.. It gives only Docs in result, but when on same search page we change the serach criteria from "created by" to Other like"created On"  it will gives us EPMDocs and Normal Docs in result set..

Its only not Working on "Created By " & "Modifyed By" criteria... all other criteria works fie..

One Another thing.. when i select Exclusively Search Type as" Customized EPMDoc" and in search Criteria"Created By", it not gives any result.. but when i remove "Created By" criteria it will gives results..

Anyone knows where to to changes to gives result for "created By " Criteria Which gives us both EPM and WTDocs in result set of Customized Type

Any Help will greate..

Thanks,

Vivek